Acetabular reamer

Abstract

An acetabular reamer is provided with a shaft having opposed front and rear ends. A mounting cap is securely connected to the front end of the shaft and includes a skirt having an interior surface spaced radially outwardly from the shaft and an opposed non-cylindrical exterior surface. At least one aperture extends through the skirt. A locking spring is disposed adjacent the interior surface of the skirt and includes a locking detent extending through the aperture in the skirt. The spring can be deflected radially inwardly to bring the detent into alignment with the exterior surface of the skirt. A reamer head is mountable over the mounting cap such that the rear wall of the reamer head deflects the spring radially inwardly during mounting and unmounting. In the fully mounted condition of the reamer head, the locking detent of the spring engages an inwardly facing surface of the rear wall of the reamer head. The° acetabular reamer further includes a sleeve slidably and rotatably disposed around the shaft. The forward end of the sleeve can be gravitationally advanced into the annular space between the shaft and the skirt to prevent the inward deflection of the spring. Thus, the sleeve and the spring cooperate to prevent unintentional separation of the reamer head from the mounting cap.

We claim: 
     
       1. A surgical reamer, comprising: shaft means for delivering rotatable driving forces;   reamer means selectively engageable and disengageable with the shaft means; and   gravitationally responsive locking means mounted to the shaft means for positively locking the reamer means to the shaft means when the surgical reamer is disposed in a first gravitational orientation and for unlocking the reamer means from the shaft means when the surgical reamer is disposed in a second gravitational orientation.   
     
     
       2. A surgical reamer as in claim 1, wherein the locking means comprises a sleeve means slidably mounted to the shaft means for slidable movement toward the reamer means in the first gravitational orientation of the surgical reamer for locking the reamer means to the shaft means, said sleeve means being slidably moveable along the shaft means away from the reamer means in the second gravitational orientation of the surgical reamer for unlocking the reamer means from the shaft means. 
     
     
       3. A surgical reamer as in claim 2, wherein the locking means further comprises at least one deflectable detent biasingly mounted to the shaft means for resiliently retaining the reamer means on the shaft means, the sleeve means being engageable with the deflectable detent in the first gravitational orientation of the surgical reamer for preventing deflection of the detent and thereby positively locking the reamer means to the shaft means, the sleeve means being spaced from the deflectable detent in the second gravitational orientation of the surgical reamer, for enabling deflection of the detent and thereby unlocking the reamer means from the shaft means. 
     
     
       4. A surgical reamer as in claim 1, wherein the shaft means comprises a mounting cap at an end thereof remote from the surgical drill, the reamer means being engageable with the mounting cap, the locking means comprising at least one deflectable detent, such that in an undeflected position said detent secures said reamer means on said mounting cap, and such that in a deflected condition said detent permits separation of said reamer means from the mounting cap of the shaft means, said locking means comprising a sleeve slidably mounted to the shaft means, such that in the first gravitational orientation of the surgical reamer, the sleeve slides toward the mounting cap to prevent deflection of the detent and thereby locking the reamer means to the mounting cap, and such that in the second gravitational orientation of the surgical reamer, the sleeve slides away from the mounting cap to permit deflection of the locking detent and thereby enabling removal of the reamer means from mounting cap. 
     
     
       5. A surgical reamer comprising: shaft means for delivering rotatable driving forces from a surgical drill, the shaft means comprising a mounting cap at an end thereof remote from the surgical drill;   reamer means selectively engageable and disengageable with the mounting cap of the shaft means; and   gravitationally responsive locking means mounted to the shaft means for positively locking the reamer to the shaft means when the surgical reamer is disposed in a first gravitational orientation and for unlocking the reamer means from the shaft means when the surgical reamer is disposed in a second gravitational orientation, the locking means comprising a generally semi-circular leaf spring, a pair of detents mounted at generally diametrically opposed locations on the leaf spring such that in an undeflected condition of said leaf spring, said detents secure said reamer means on said mounting cap, and such that in a deflected condition of said leaf spring, said detents permit separation of said reamer means from the mounting cap of the shaft means, said locking means further comprising a sleeve slidably mounted to the shaft means, such that in the first gravitational orientation of the surgical reamer, the sleeve slides toward the mounting cap to prevent deflection of the leaf spring and thereby locking the reamer means to the mounting cap, and such that in the second gravitational orientation of the surgical reamer, the sleeve slides away from the mounting cap to permit deflection of the leaf spring and thereby enabling removal of the reamer means from the mounting cap.   
     
     
       6. An acetabular reamer comprising: a shaft having opposing front and rear ends;   a mounting cap rigidly connected to the front end of said shaft, said cap having an axially extending skirt with an interior surface spaced radially from the shaft and an opposed exterior surface, at least one hole extending from the interior surface to the exterior surface;   a locking spring disposed against the interior surface of said skirt, at least one detent on the spring disposed and dimensioned to project through the hole in the skirt and beyond the exterior surface thereof, said spring being deflectable inwardly to move the detent into alignment with the exterior surface of the skirt;   a sleeve slidably and rotatably mounted on the shaft and having opposed front and rear ends, the front end being selectively slidably advanceable between the shaft and the spring for preventing inward deflection of the spring; and   a reamer head having a front wall and a rear wall with a non-cylindrical aperture engageable over the exterior surface of the skirt, said rear wall being configured to urge the detent radially inwardly for enabling movement of the rear wall rearwardly past the detent and thereby enabling the spring to resiliently return to a position where the detent engages the rear wall intermediate the front and rear walls of the reamer head, whereby the sleeve is selectively slidably advanceable forwardly for preventing inward deflection of the spring and thereby locking the reamer head to the mounting cap.   
     
     
       7. An acetabular reamer as in claim 6, wherein the skirt of the mounting cap defines opposed front and rear ends, the aperture extending through the skirt intermediate the front and rear ends, an outwardly extending flange disposed at the rear end of the skirt and defining a diametric cross-section greater than the cross-section of aperture in the reamer head. 
     
     
       8. An acetabular reamer as in claim 6, wherein the skirt of the mounting cap includes two holes extending through the skirt at spaced apart locations thereon, the locking spring including two detents projecting through the respective holes in the skirt of the mounting cap. 
     
     
       9. An acetabular reamer as in claim 8, wherein the holes extending through the skirt of the mounting cap are disposed at diametrically opposed locations on the skirt. 
     
     
       10. An acetabular reamer as in claim 6, wherein the locking spring is formed from a flat strip of metal, and wherein the detent is defined by at least one rivet staked to the flat strip of metal. 
     
     
       11. An acetabular reamer as in claim 10, wherein the rivet includes a generally semi-spherical head projecting through the hole in the skirt of the mounting cap.